Recently, control systems have been proposed that include an instruction output device that outputs a power supply/shutoff instruction to supply power from a battery to a load or to shut off the supply of power, and a power supply control device that supplies power to the load and shuts off the supply of power in accordance with the power supply/shutoff instruction that is output by the instruction output device (see Patent Document 1).
In the control system disclosed in Patent Document 1, the power supply control device supplies power and shuts off the supply of power by switching on/off a switch that is provided midway on an electric wire connecting the battery and the load. A turning on/off instruction to turn on or off the load is input to the instruction output device from the outside, and the instruction output device outputs the power supply/shutoff instruction that corresponds to the input turning on/off instruction to the power supply control device. Furthermore, the instruction output device calculates the temperature of the electric wire based on the value of a current flowing from the battery to the load.
In the control system disclosed in Patent Document 1, if in the state in which the power supply control device is instructed to supply power, the temperature of the electric wire that was calculated based on the value of the current flowing from the battery to the load does not increase for a predetermined time period, the instruction output device determines that there is an abnormality in a load circuit including the battery, the switch, the power supply control device, and the load, and specifies that the reason of the abnormality is wire breakage (open circuit). As described above, in the control system disclosed in Patent Document 1, the instruction output device determines whether or not the supply of power to the load is abnormal based on the value of the current flowing from the battery to the load, and specifies, if it is determined that the supply is abnormal, the reason of the abnormality.